Parsing refactor

[Dananji]

Related issue: #606

Changes:

• Remove use parseManifest from manifesto.js as much as possible. Instead use JSON blob returned from the fetch request to read and parse relevant data for Ramp components (this is equivalent to loadManifest function in manifesto.js).
• Move parsing of custom start, canvas information, and rendering files to IIIFPlayerWrapper component as these values are needed in different components. Store this information in state to make available them to child components. This helps to save this information into state before storing manifest, which triggers rendering of child components.
• Move parsing and storing of auto-advance, isPlaylist, and annotation service information into manifest-context as these can be parsed and stored asynchronously in state to be used later.
• Parse all resource related information in a Canvas in getMediaInfo function including placeholderCanvas.

Not changed:

• Use of parseManifest in parsing structures as this makes the parsing of ranges easier than using the JSON object of manifest. And this code is more clear and readable.

Note

I missed the previous work done on the refactor done by @cjcolvar. But we should probably re-visit that when doing the state management work. I think this work is more related to asynchronous state management than parsing, which is one of the things we should probably look at as part of that refactor.

[cjcolvar]

This looks great! Getting rid of most of those parseManifest calls as well as manifesto objects and methods cleans it up a lot and probably will make it faster too!

I had a few small questions/suggestions but none of them are blocking.